THE TIDAL DELTA-FLUVIAL SEDIMENTATION AND COAL ACCUMULATION OF SHANXI FORMATION IN PINGOU MINING AREA,SOUTH WESTERN EDGE OF INNER MONGOLIA

The detailed field observation and laboratory study show that the Shanxi Formation was formed in tidal delta fluvial environments.The fluviation included braided meander stream and high curving degree meander stream.The tidal delta was marked by the development of tidal deposition.tidal sand bar and tidal channel deposits were the main components of tidal deposition.The existence of tidal delta shows that the edpositional basin was influenced by sea flowage.The coal accumulation developed in the environments of channel-bank swamp,the tidal flat developed at the abanoned tidal sand bar and peat swamps developed from filling shallowed distributary bays.This paper analyses the coal accumulation characteristics of every depositional environments.